The fibroblast in morphogenesis and fibrosis: cell topography and surface-related functions

'Fibroblast' is a generic term for a population of cells responsible for the establishment, maintenance and repair of three-dimensional form in multicellular organisms. These cells are a major, semi-permanent resident of the 'extracellular space' and the fibroblast compartmentalizes this space to various purposes during the formation of collagen fibrils and fibril bundles. The boundaries of these extracellular compartments blend and overlap, but discrete regions can be identified which are involved in collagen fibril assembly and fibril bundle assembly. The formation of these extracellular compartments in both the tendon and cornea results from a series of fusions of membrane-limited structures, beginning with collagen secretory vacuoles fusing with the cell surface to form deep surface recesses within which fibrils assemble; and progressing through the lateral fusion of these recesses with the consequent formation of fibril bundles. The topography of the fibroblast is also specialized for matrix anchorage, for matrix and cell repositioning, and for matrix degradation.